Question

ethylene (c₂h₄) is a gaseous hydrocarbon which is used to synthesize different types of polymers. which of the following diagrams represent the electron dot structure of ethylene?

Explanation:

Step1: Determine valence electrons

Carbon has 4 valence - electrons and hydrogen has 1 valence - electron. In $C_2H_4$, there are 2 carbon atoms and 4 hydrogen atoms. Total valence electrons = $2\times4 + 4\times1=12$.

Step2: Consider bonding in ethylene

Each carbon - hydrogen bond uses 2 electrons. There are 4 C - H bonds, using 8 electrons. The remaining 4 electrons form a double - bond between the two carbon atoms.

Step3: Write electron - dot structure

The correct electron - dot structure of ethylene ($C_2H_4$) has each carbon atom bonded to two hydrogen atoms and a double - bond between the two carbon atoms. The structure is $H:\ddot{C}::\ddot{C}:H$ with two hydrogen atoms attached to each carbon atom above and below the carbon - carbon double - bond.

Answer:

The first option (where there is a double - bond between the two carbon atoms and each carbon is bonded to two hydrogen atoms) is the correct electron - dot structure of ethylene.